Re: [PATCH v3 5/6] arm64: dts: qcom: sdm845: Add OPP table support to UFSHC

[Viresh Kumar]

On 12-09-23, 12:29, Manivannan Sadhasivam wrote:
> On Mon, Sep 11, 2023 at 04:15:10PM +0300, Dmitry Baryshkov wrote:
> > I'd say, I'm still slightly unhappy about the 0 clock rates here.
> 
> Neither do I. But it is the only viable option I could found.
> 
> > We need only three clocks here: core, core_clk_unipro and optional
> > ice_core_clk. Can we modify ufshcd_parse_operating_points() to pass only
> > these two or three clock names to devm_pm_opp_set_config() ? The OPP core
> > doesn't need to know about all the rest of the clocks.
> > 
> 
> We need to enable/disable all of the clocks, but only need to control the rate
> for these 3 clocks. So we cannot just use 3 clocks.
> 
> If the OPP table has only 3 entries (omitting the gate-only clocks), then we
> need some hack in the driver to match the rates against the clock entries. Doing
> so will result in hardcoding the clock info in the driver which I do not want to
> do.
> 
> If we have something like "opp-hz-names" to relate the rates to clock-names, it
> might do the job. But it needs some input from Viresh.

I have already given an option earlier about this [1]. You can change the order
of clks in the "clock-names" field, so that the first three are the one with
valid frequencies. You shouldn't need much of the hacks after that I guess.

Or maybe I missed something else now, talked about this a long time ago :)

-- 
viresh
[1] https://lore.kernel.org/all/20230713040918.jnf5oqiwymrdnrmq@vireshk-i7/